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In a recently published PNAS article, we studied the identifiability of genomic samples using machine learning methods [Lippert et al., 2017]. In a response, Erlich [2017] argued that our work contained major flaws. The main technical critique of Erlich [2017] builds on a simulation experiment that shows that our proposed algorithm, which uses only a genomic sample for identification, performed no better than a strategy that uses demographic variables. Below, we show why this comparison is misleading and provide a detailed discussion of the key critical points in our analyses that have been brought up in Erlich [2017] and in the media. Further, not only faces may be derived from DNA, but a wide range of phenotypes and demographic variables. In this light, the main contribution of Lippert et al. [2017] is an algorithm that identifies genomes of individuals by combining multiple DNA-based predictive models for a myriad of traits.

Prediction of human physical traits and demographic information from genomic data challenges privacy and data deidentification in personalized medicine. To explore the current capabilities of phenotype-based genomic identification, we applied whole-genome sequencing, detailed phenotyping, and statistical modeling to predict biometric traits in a cohort of 1,061 participants of diverse ancestry. Individually, for a large fraction of the traits, their predictive accuracy beyond ancestry and demographic information is limited. However, we have developed a maximum entropy algorithm that integrates multiple predictions to determine which genomic samples and phenotype measurements originate from the same person. Using this algorithm, we have reidentified an average of >8 of 10 held-out individuals in an ethnically mixed cohort and an average of 5 of either 10 African Americans or 10 Europeans. This work challenges current conceptions of personal privacy and may have far-reaching ethical and legal implications.

The eukaryotic phylum Apicomplexa encompasses thousands of obligate intracellular parasites of humans and animals with immense socio-economic and health impacts. We sequenced nuclear genomes of Chromera velia and Vitrella brassicaformis, free-living non-parasitic photosynthetic algae closely related to apicomplexans. Proteins from key metabolic pathways and from the endomembrane trafficking systems associated with a free-living lifestyle have been progressively and non-randomly lost during adaptation to parasitism. The free-living ancestor contained a broad repertoire of genes many of which were repurposed for parasitic processes, such as extracellular proteins, components of a motility apparatus, and DNA- and RNA-binding protein families. Based on transcriptome analyses across 36 environmental conditions, Chromera orthologs of apicomplexan invasion-related motility genes were co-regulated with genes encoding the flagellar apparatus, supporting the functional contribution of flagella to the evolution of invasion machinery. This study provides insights into how obligate parasites with diverse life strategies arose from a once free-living phototrophic marine alga., King Abdullah University of Science and Technology (KAUST; Council of Scientific and Industrial Research; National Institute of Allergy and Infectious Diseases (NIAID); Australian Research Council (ARC); Monash University; National Health and Medical Research Council (NHMRC); Czech Science Foundation (Grantova´ agentura Ceske´ republiky)

Xylella fastidiosa is a Gram-negative bacterium belonging to the gamma subgroup of the proteobacteria (Wells et al. 1987). This microorganism is an important plant pathogen causing many economically important crop diseases, such as Pierce's disease (PD) of grapevine and citrus variegated chlorosis in citrus (Moller et al. 1974; Purcell 1997). Almond leaf scorch was first described in 1974 (Moller et al. 1974), and electron microscope studies indicated the presence in almond of the same bacterium previously associated with PD of grapevines (Mircetich et al. 1976). Cross-inoculation studies showed that PD and the almond leaf scorch strains were pathogenic to both almond and grape (Davis and Thompson 1980). Oleander leaf scorch was first noticed in 1994 in southern California. The glassy-winged sharpshooter, Homalodisca coagulata, was found to be the vector for this bacterium. It is possible that several other varieties of sharpshooters can transmit X. fastidiosa between oleander plants (Purcell et al. 1999). The oleander leaf scorch strain could not be reisolated from grapevine in a greenhouse after inoculation using needle puncture (Purcell et al. 1999). This result provides evidence for host specificity among strains of X. fastidiosa. Previous studies classified X. fastidiosa as a single species, but differentiated members of the species, depending on such criteria as host specificity and pathogenicity (Hendson et al. 2001 and references therein). We define each strain of X. fastidiosa to be a pathovar for a specific plant, as suggested previously (Hendson et al. 2001). We will therefore refer throughout to the citrus, almond, and oleander strains as Xf pv citrus (XFA), Xf pv almond (XFX), and Xf pv oleander (XFY). The complete genome sequence of the X. fastidiosa 9a5c strain (XFA), which causes citrus variegated chlorosis , was recently published (Simpson et al. 2000). In this study, we report the gapped-genome sequences of Xf pv almond (Dixon strain) (XFX) and Xf pv oleander (Ann-1 strain) (XFY) and compare them to the complete genomic sequence of XFA. Here we present highlights of the first functional reconstruction of a phytopathogenic microbe based on the three sequenced genomes. This approach has led us to the identification of a putative drug target in the aerobic respiratory chain of this organism, as well as to a prediction of the specific growth requirements of this bacterium, which were used to develop a defined medium for optimal growth. Furthermore, based on a global alignment of the proteomes for these genomes, we identified a region in XFA that is absent in the other two genomes that potentially encodes host-specific functions. Comparisons of curated pathways and their components present in the complete XFA genome relative to the gapped XFY and XFX genomes allows the prediction of functions potentially missed during gapped-genome sequencing. Such an approach provides an added level of quality control to the analysis of sequenced genomes.

Novel drug targets are required in order to design new defenses against antibiotic-resistant pathogens. Comparative genomics provides new opportunities for finding optimal targets among previously unexplored cellular functions, based on an understanding of related biological processes in bacterial pathogens and their hosts. We describe an integrated approach to identification and prioritization of broad-spectrum drug targets. Our strategy is based on genetic footprinting in Escherichia coli followed by metabolic context analysis of essential gene orthologs in various species. Genes required for viability of E. coli in rich medium were identified on a whole-genome scale using the genetic footprinting technique. Potential target pathways were deduced from these data and compared with a panel of representative bacterial pathogens by using metabolic reconstructions from genomic data. Conserved and indispensable functions revealed by this analysis potentially represent broad-spectrum antibacterial targets. Further target prioritization involves comparison of the corresponding pathways and individual functions between pathogens and the human host. The most promising targets are validated by direct knockouts in model pathogens. The efficacy of this approach is illustrated using examples from metabolism of adenylate cofactors NAD(P), coenzyme A, and flavin adenine dinucleotide. Several drug targets within these pathways, including three distantly related adenylyltransferases (orthologs of the E. coli genes nadD , coaD , and ribF ), are discussed in detail.

Xylella fastidiosa ( Xf ) causes wilt disease in plants and is responsible for major economic and crop losses globally. Owing to the public importance of this phytopathogen we embarked on a comparative analysis of the complete genome of Xf pv citrus and the partial genomes of two recently sequenced strains of this species: Xf pv almond and Xf pv oleander , which cause leaf scorch in almond and oleander plants, respectively. We report a reanalysis of the previously sequenced Xf 9a5c (CVC, citrus) strain and the two “gapped” Xf genomes revealing ORFs encoding critical functions in pathogenicity and conjugative transfer. Second, a detailed whole-genome functional comparison was based on the three sequenced Xf strains, identifying the unique genes present in each strain, in addition to those shared between strains. Third, an “ in silico ” cellular reconstruction of these organisms was made, based on a comparison of their core functional subsystems that led to a characterization of their conjugative transfer machinery, identification of potential differences in their adhesion mechanisms, and highlighting of the absence of a classical quorum-sensing mechanism. This study demonstrates the effectiveness of comparative analysis strategies in the interpretation of genomes that are closely related.

We present a complete DNA sequence and metabolic analysis of the dominant oral bacterium Fusobacterium nucleatum . Although not considered a major dental pathogen on its own, this anaerobe facilitates the aggregation and establishment of several other species including the dental pathogens Porphyromonas gingivalis and Bacteroides forsythus . The F. nucleatum strain ATCC 25586 genome was assembled from shotgun sequences and analyzed using the ERGO bioinformatics suite ( http://www.integratedgenomics.com ). The genome contains 2.17 Mb encoding 2,067 open reading frames, organized on a single circular chromosome with 27% GC content. Despite its taxonomic position among the gram-negative bacteria, several features of its core metabolism are similar to that of gram-positive Clostridium spp., Enterococcus spp., and Lactococcus spp. The genome analysis has revealed several key aspects of the pathways of organic acid, amino acid, carbohydrate, and lipid metabolism. Nine very-high-molecular-weight outer membrane proteins are predicted from the sequence, none of which has been reported in the literature. More than 137 transporters for the uptake of a variety of substrates such as peptides, sugars, metal ions, and cofactors have been identified. Biosynthetic pathways exist for only three amino acids: glutamate, aspartate, and asparagine. The remaining amino acids are imported as such or as di- or oligopeptides that are subsequently degraded in the cytoplasm. A principal source of energy appears to be the fermentation of glutamate to butyrate. Additionally, desulfuration of cysteine and methionine yields ammonia, H 2 S, methyl mercaptan, and butyrate, which are capable of arresting fibroblast growth, thus preventing wound healing and aiding penetration of the gingival epithelium. The metabolic capabilities of F. nucleatum revealed by its genome are therefore consistent with its specialized niche in the mouth.

Brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and Malta fever in humans. The genome of B. melitensis strain 16M was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 ORFs. By using the bioinformatics suite ERGO, 2,487 (78%) ORFs were assigned functions. The origins of replication of the two chromosomes are similar to those of other α-proteobacteria. Housekeeping genes, including those involved in DNA replication, transcription, translation, core metabolism, and cell wall biosynthesis, are distributed on both chromosomes. Type I, II, and III secretion systems are absent, but genes encoding sec -dependent, sec -independent, and flagella-specific type III, type IV, and type V secretion systems as well as adhesins, invasins, and hemolysins were identified. Several features of the B. melitensis genome are similar to those of the symbiotic Sinorhizobium meliloti .

GOLD is a comprehensive resource for accessing information related to completed and ongoing genome projects world-wide. The database currently provides information on 350 genome projects, of which 48 have been completely sequenced and their analysis published. GOLD was created in 1997 and since April 2000 it has been licensed to Integrated Genomics. The database is freely available through the URL: http://igweb.integratedgenomics.com/GOLD/.